Cytomorphologic Criteria: Sheets of parabasal cells with slight air drying. Interpretation is NILM.

Explanatory Notes: Atrophic parabasal cells can be confused with squamous metaplasia. The background and cell pattern may be useful in distinguishing the two.

Follow-up: The transformation zone component may be difficult to assess in atrophy. In such cases, the laboratory may elect to make a comment about the difficulty of assessing the transformation zone component (does not apply for vaginal smears)